Process of making pistons



Patented J 111 26 19200 J. FLAMMANG. PROCESS 0F MAKING PISTO APPLICATION FILEDIFEB. 21, 1918. 1,347,449.

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JOHN FLAMMANG, or s'r. Louis,

PROCESS OF MAKING PISTONS.

, Specification of Letters Patent.

Patented July 20, 1920.

Application filed February 27, 1918. Serial No. 219,363.

To all whom it may concern:

Be it known that I JOHN FLAMMANG, a citizen of the United States, re'sidingat the city of St. Louis and State of Missouri, have invented a new and useful Processof Making Pistons, of which the following is a specification.

This invention relates to the art of manufacturing pistons.

An object of the invention is to improve the art of manufacturing pistons whereby pistons may be produced that will function properly and with a high degree of efiiciency without the use of piston rings or pacl nng.

A specific object of the invention is to provide a method or mode of procedure of manufacturing pistons which will function properly and with a high degree of BlIlClBIlCY without the use of piston rings or any kind of packing and which, because of qualities inherent in the construction of the piston, will cooperate so effectively with the cyl nder that the passage of gas, steam or the like between the piston and the cylinder is prevented.

Various other objects and advantages will appear from the following description in which reference is made to the accompanying drawings illustrating a piston in several stages of its construction in accordance with the present invention, and in wh1ch I Figure 1 is a view partly in section illustrating a form of casting which may be used in the construction of the piston body.

Fig. 1 is a plan view of the casting.

Fig. 2 is a view illustrating the casting after several stages on steps of treatment.

Fig. 8 is a view of the casting after the metal has been placed under tension so that when the piston is finished and placed in the cylinder the piston will impart pressure against the cylinder wall'all around.

Fig. 4: is an elevation of the casting while the metal above the wrist pin is held under tension ready for the casting to be finished as to its circumferential surface.

Fig. 5 is a View illustrating the casting held under tension within a cylinder, in which the treatment of the body of the piston is finished and made ready for the head plate to be applied thereto.

Fig. 6 is an elevation of a finished piston made in accordance with my invention.

Fig. 7 is a sectional view of the piston mounted within a cylinder.

The body of the piston is made from a casting which is treated so that the upper portion of the casting in its finished form is of a diameter larger than the diameter of the cylinder for which the piston is intended, and which when placed in the cylinder is held under tension so that the piston body will impart pressure against the wall of the cylinder all around thus dispensing with the use of piston rings and packing. The treatment to which the piston is subjected may consist either in grinding the piston to the form desired, or in spreading the piston by the wrist pin as hereinafter explained. The resiliency of the material of the'body of the piston is utilized so that the piston can expand and contract in conformity with the requirements in order to maintain perfect cooperation with the wall of the cylinder and prevent the passage of gas or steam between the piston and the cylinder. The resiliency of the metal may be utilized by different methods and in describing my invention by making reference to the annexed drawing, I do not of course confine myself to the use or practice of the present invention in manufacturing pistons of the identical construction illustrated. The drawings are only for the purpose of illustrating one form of piston which may satisfactorily be constructed by use of m present process.

In the particular embodiment illustrated the body of the piston is manufactured from a casting which in its original form illustrated in Fig. 1, comprises a lower ring 1, an upper ring 2, a number of connections 3 integrally uniting the upper and lower rings, and bosses .t in which the wrist pin of the finished piston is mounted. In its original condition the casting also includes two arms 5 extending inwardly from diametrically opposite sides of the upper ring in the plane of the bosses 4; and said arms, as shown, have upward extensions 6.

The next stages or steps in the construction of the piston by my present process consist in the formation of inwardly and downwardly incline-d holes 7 through the connections 3 and the bosses l and cutting the upper ring in two places at diametrically opposite points, as shown at 8, in order to form an upper ring composed of separate segmental sections which are adapted to press against the wall of the cylinder for which the piston is intended by the resiliency of the metal of the piston. Also, preferably, though not essentially, the body of the casting is turned or ground so as to give it a slightly tapered shape, larger at its upper end as will be understood by reference to Fig. 2.

The connections 3 are next placed under tension by inserting a wrist pin 9 in the sition and the proper tension'is placed within the terial is holes '7. The wrist pin fits closely within the holes and in order to insert the wrist pin it is necessary to bend or spread apart to a slight extent the connections 3 until the holes are in accurate alinement. The wrist pin will hold the material in that shape so that the connections 3 are at all times under tension.

Next the two separated parts of the ring 2 are forced toward each other in order to bend inwardly and place under tension the connections 3 above the wrist pin. This may be accomplished in any desired manner as, for instance, by passing a bolt 10 through the extensions 6 and turning the nut on the bolt until the segmental sections of the ring 2 are drawn to the desired pogiven the connections 3 above the wrist pin. While the casting is thus held under tension the periphery of the casting is ground or turned and finished. The upper ring is finished to the diameter of the cylinder for which it'is intended, while the lower ring 1 is of slightly less diameter than the diameter of the cylinder. Thus, when the piston is cylinder after being finished, pressure will be imparted against the cylinder wall all around'by the segmental sections of the ring 2, due to the fact that when the ring was finished it was held under tension to the diameter of the cylinder, and when released from the compressing device the resiliency of the'metalwill cause the ring 2 to eXert the required pressure against the wall of the cylinder.

After the periphery of the piston has been finished to give the upper ring a diameter the same as the diameter of the cylinder for which the piston is intended, while the maheld under tension as described, the piston is placed within a cylinder 11 (Fig. 5) of the same diameter as the diameter of the cylinder for which the piston is intended, thus holding the tension after the bolt 10 is removed.

The upper portion of the ring 2 is then cut away below the arms 5 and in the form of piston shown an internal groove 12 is formed in the ring 2. Also, either before the piston is placed in the cylinder or after removal therefrom as desired, a number of circumferentialgrooves 13 are formed in the lower ring 1, which grooves are adapted to receive an oil or lubricant whereby the necessary lubricant is applied between the piston and in which it operates.

' ends of the ring piston compressed under top plate 14 of the piston the ring 2 and interlocked flange 15 engaging within the groove 12, or, as preferred, by keys 16 seated in grooves in the open ends of the ring 2 and engaging in grooves in the top plate 14:, so that said keys will be eifective not only to hold the top plate in connection with the piston body but will also be effective to close the spaces between the open 2 and thus prevent passage. of gas through said spaces.

The split upper ring of the spread or opened sufiiciently to permit the top plate to be applied, permitting the flan e to pass inside the opened ring until said flange seats in the groove 12, as shown.

The upper edge of the ring 1 is beveled to provide a scraping edge 17 which during upward movement of the piston will scrape the oil from the cylinder wall; and the lower edge of the ring 2 is beveled to provide a scraping edge 18 which during downward movement of the piston will scrape the oil from the cylinder wall.

By reference to Figs. 6 and 7 it will be understood that the finished piston has a bodycomposed of an open upper ring of slightly larger diameter than the diameter of the cylinder for which the piston is intended, and that when the piston body is compressed within the cylinder. the segmental sections of the upper ring will impart a pressure against the cylinder wall all around suflicient to prevent the passage of gas or steam and that the spaces between the ends of the segmental sectionsof the upper ring are also closed againstthe pas sage of gas or steam by the keys 16. v

It will be apparent that the order in which the stages of treatment are performed in the manufacture of the piston is unimportant, and that the order of such performance may be optionally varied. 'Iclaim: V

1. The process of making a piston which consists in dividing the upper portion of the piston body into segmental. sections; drawing the segmental sections toward each other; and forming the exterior periphery of the segmental sections in cylindrical form while the said sections are held drawn together.

2. The process of making a piston, which consists in forming a piston body. ofra lower ring, an upper ring and connections integrally uniting the upper and lower rings; splitting the upper ring into segmental sections; drawing the segmental sections of the upper ring toward each other to place the material under tension; and finishing the piston to a size in which the upper ring while compressed under tension is of the same diameter as the diameter of the cylinder for which the pistonis intended.

The head or is seated upon therewith by a piston may be,

3. The process of making a piston which consists in forming a piston body of a lower ring, an upper ring, and connections integrally uniting the upper and lower rings; splitting the upper ring into segmental sections; tensioning the upper ring; and finishing the piston.

4. The process of forming a piston which consists in forming a piston body of a lower ring, an upper ring integrally connected with the lower ring; splitting the upper ring into segmental sections; holding the material under tension; finishing the piston while under tension to a size in which the upper ring is of the same diameter as the diameter of the cylinder for which the piston is intended; and connecting a top plate to the piston body.

5. The process of forming a piston which consists in forming a piston body of a lower nections uniting the upper and lower rings; forming holes inclining inwardly and downring and an upper ring, and integral conwardly through said connections; inserting a wrist pin in said holes whereby said connections are placed under tension; tensioning the metal above the wrist pin; and finishing the piston.

6. The process of forming a piston which consists in forming a piston body of a lower ring, an upper ring, and connections integrally uniting said rings; splitting the upper ring into segmental sections; spread- .ing said connections apart to hold the material under tension; drawing the upper ring sections toward each other to place the material under tension; and finishing the surface of the piston.

7. The process of making a piston which consists in dividing the upper portion of the piston body into segmental sections; tensioning said sections, and finishing the exterior surfaces of said sections while they are under tension by forming the exterior surfaces on the same radius of curvature.

JOHN FLAMMANG. 

